The present invention relates to vehicle tie-down systems for use in securing vehicles for transport on rail cars and, more particularly, relates to a system utilizing a double chain in a triangulated configuration.
It is common in tie-down systems to secure the four corners of a vehicle to a structure on a rail car, or the like. This is commonly referred to as "four-point tie-down." It would be desirable to provide a system utilizing a "two-point tie-down" on the front and rear of the same side of the vehicle, or a single device on each side of the vehicle, since a substantial labor savings could result in loading of the vehicles. One problem, however, has been the concern with safety and stability, since single-chain constructions have been used. With single-chain structures in a two-point system, in the event one chain breaks or is not connected properly, forward and rearward stability of the vehicle would be lost. In the system of the present invention, each tie-down point has, in a sense, a double-chain structure; and since the chain is connected in a triangulated configuration, each tie-down point independently resists forward and rearward movement. Thus, in the system of the present invention in the event the chain breaks or is improperly connected at one tie-down point, the other chain at the other tie-down point will provide the means necessary to maintain the fore and aft stability of the vehicle. As will be seen, even though a single-chain structure is used to define the triangulated structure, a break in one section of the chain would still leave the other section intact to assist the chain at the other point in securing the vehicle.
Further, with reference to the two-point tie-down system of the present invention, it has been found that the verticle impact loads transmitted into the vehicle during transport are reduced. It is believed that this occurs because the suspension system on the untied portion of the vehicle can function less restrictedly than when all four points are tied down and, hence, loads imparted to the vehicle can be more readily absorbed.
Therefore, it is an object of the present invention to provide a novel two-point tie-down system for vehicles generally of the type as described.
It is another object of the present invention to provide a novel two-point tie-down system utilizing a single chain at each tie-down point connected in a triangulated configuration.
It is a common practice to pull the vehicle down against its suspension to provide a predesired amount of compressive reload. In the system of the present invention, a bi-directional tie-down assembly is used in conjunction with a separate ratcheting device. The bi-directional tie-down assembly is selectively movably located in a track on the rail car and can be fixed at selected locations. The bi-directional tie-down assembly has a construction providing for the triangulated chain construction. As the chain is tensioned pulling the vehicle closer to the rail, the apex of the triangle moves closer to what would be its base. However, the base does not change in length, thereby assuring adequate separation of the two legs of the triangle, and hence thereby assuring good forward and rearward retention of the vehicle.
Once initial vertical pull down of the vehicle is attained against the vehicles own suspension system, further vertical movement of the chain sections has no effect on the fore and aft movement of the vehicle allowing close bumper to bumper loading of vehicles.
As previously stated, in the present system, the triangulated chain assembly is tensioned by a separate ratcheting device, which can be any of several constructions well known in the art. The use of a separate ratchet provides an advantage, since it can be located remotely from the bi-directional tie-down assembly, including the triangulated chain. This permits the triangulated chain to be connected to the ratcheting device via a single chain extending from the bi-directional tie-down assembly, thereby permitting the ratchet assembly to be located at the most convenient point for ease of operator actuation.
Therefore, it is another object of the present invention to provide a novel tie-down system including a bi-directional tie-down assembly adapted to provide a triangulated chain configuration and a separate chain take-up device or ratchet device locatable remotely therefrom.
It is another object of the present invention to provide a novel tie-down system including bi-directional tie-down assembly adapted to provide a triangulated chain construction with the base of the defined triangle remaining constant in length regardless of the tensioning of the chain.
In the present invention, a novel hook construction is shown permitting a single, continuous chain to define the triangulated chain construction. Therefore, it is another object of the present invention to provide a novel hook construction for use in the above-described system.
It is another general object to provide a novel tie-down system for securing vehicles to a rail car for transport thereby.